Light-colored sulfonation products



United States Patent LIGHT-COLORED SULFONATION PRODUCTS Horst Baumanu,Hilden, Rhineland, and Werner Stein,

Erkrath-Unterbach, Germany, assignors to Henkel &

Cie GmbH, Dusseldorf, Germany N0 Drawing. Filed May 3, 1967, Ser. No.635,670 Claims priority, applicatirn GGermany, July 1, 1966,

Int. Cl. Clld 1/J 2; C07c 143/16 US. Cl. 252-161 Claims ABSTRACT OF THEDISCLOSURE Process for preparing surface-active sulfonates compris ingreacting an olefin having 8 to 22 carbon atoms in its molecule with atleast one member selected from the group of chlorosulfonic acid andgaseous sulfur trioxide diluted with an inert gas as sulfonating agent,in the presence of a polyglycol ether having the formula:

The present invention relates to the sulfonation of olefins to producelight-colored olefin sulfonates having a low content of non-surfactantcomponents.

It has been proposed in the prior art to sulfonate olefins which have aterminal double bond by treating them with gaseous sulfur trioxidediluted with an inert gas, and to convert the sulfonated products thusproduced by hydrolysis into water-soluble sulfonates. As in thisprocess, a high degree of sulfanation is desirable in order to avoidhaving to separate unsulfonated components, a relatively high excess ofsulfonating agent has to be employed in the sulfonation. As a result,the sulfonates, which are obtained as final products, are relativelydarkcolored, and require bleaching with oxygen-yielding bleaches priorto their technical use. The time required for the bleaching process canbe shortened or the amount of bleach that is necessary can beconsiderably reduced by carrying out the sulfonation of the olefins intwo stages. However, a one-stage process is preferred if it does notentail any appreciable losses in the quality or quantity of productthereby obtained.

It is furthermore known in the prior art to carry out the sulfonation ofolefins using as the sulfonation agent chloro-sulfonic acid, or sulfurtrioxide, the sulfonation being effected in the presence of inertsolvents such as a parafi'inc hydrocarbon, chlorinated hydrocarbon orliquid sulfur dioxide. The results achieved have not been satisfactory,and it has, therefore, been proposed to use solvents which form stableaddition products with sulfur trioxide as, for example, dioxane. If inthe first stage of the process the sulfonating agent is dissolved indioxane and the mixture is contacted in a second stage with the olefinto be sulfonated, relatively light-colored sulfonation products areobtained. Such a process, however, is complicated, and it is alsoencumbered by necessity for the recovery of the solvent, which recoveryalways entails losses and additional expense. The large amounts ofliquid that have to be handled in a sulfonation effected according tothis procedure also necessitate the installation of larger systems.

3,492,239 Patented Jan. 27, 1970 It is, therefore, an object of thepresent invention to provide a process of producing light-colored olefinsulfonates having a low content of non-surfactant components in aone-stage procedure and without the necessity for employing liquidsolvents.

It is another object to provide a process of producing light-coloredolefin sulfonates without resort to separate bleaching treatment of thesulfonation products.

It is an additional object to provide olefin sulfonates which arecharacterized by their relatively light color and by their low contentof non-surfactants.

These and other objects will become apparent in the followingdescription and claims.

The present invention is directed to a process for the preparation ofsurface-active olefin sulfonates by the sulfonation of olefins withgaseous sulfur trioxide diluted with air or an inert gas, followed byalkaline hydrolysis, wherein as initial material for the preparation ofthe technically valuable sulfonation products there are employedaliphatic monoolefins having 8 to 22 carbon atoms in their molecules andwherein the sulfonation is carried out in the presence of a polyglycolether of the formula wherein R represents alkyl having 8 to 22 carbonatoms, R represents hydrogen or alkyl having 1 to 6 carbon atoms, m hasa value of 2 or 3, and n represents a whole number of from 1 to 20.

The aliphatic monoolefins serving as starting materials preferablycontain 12 to 18 carbon atoms and have either a middle or terminaldouble bond. The monoolefins can be straight-chain or branched-chain.Olefins having an unbranched chain, and olefins of the formula \C=CHR3R5 are preferred. In the last formula, R and R represent straight-chain,alkyl radicals having 1 to 18 carbon atoms, R represents hydrogen or astraight-chain alkyl radical having 1 to 18 carbon atoms, at least oneof the alkyl radicals containing at least 6 carbon atoms. Mixtures ofolefins of different structure and chain lengths can also be used. Thestarting olefins can be obtained in the known manner from hydrocarbonmixtures or by synthesis from olefins of low molecular weight. They donot need to be entirely pure, but may contain small amounts, though notmore than 10%, of paraffins and/or diolefins.

Examples of suitable olefins are n-decene-l, n-undecene-l,n-tridecene-l, n-dodecene-l, n-tetra-decene-l, npentadecene-l,n-hexadecene-l, n-heptadecene-l, n-octadecene-l and mixtures thereof,sec. n-decene, sec. n-undecene, sec. n-tridecene, sec. n-tetradecene,sec. n-pentadecene, sec. n-hexadecene, sec. n-heptadecene and sec.noctadecene wherein the double bond is distributed over the chain.

The polyglycol ethers of the formula as set out above can be prepared bythe conventional methods from primary or secondary alcohols by reactionthereof with ethylene oxide or propylene oxide. Mixtures of ethyleneoxide and propylene oxide can also be used, or the two alkoxides can beused successively. The alkoxylation can be followed by an alkylation ofthe free hydroxyl groups which can be conducted according to the knownand conventional methods. The two alkyl radicals R and R can bestraightor branch-chained or, alternatively, can be cyclic. Ethoxylationproducts of straight-chain primary or secondary alcohols, which arepreferred for use herein, have from 2 to 12 ethylene glycol ether groupsas Well as one free hydroxyl group, the alkyl group R having from 10 to18 carbon atoms.

Examples of suitable polyglycol ethers are the di-, tri-, tetra-,penta-, hexa-, hepta-, octa-, nona-, deca-, undeca-, and dodeca-ethyleneglycol ether of primary or secondary n-decanol, n-dodecanol,n-tetradecanol, n-hexadecanol and n-octadecanol. Said polyglycol ethersmay be etherified with 1 to 10 propylene glycol ether groups or withmethyl, ethyl, propyl or isopropyl groups.

The polyglycol ethers obtained by the addition of alkylene oxide ontolong-chain alcohols may also contain unetherified alcohols. These do notgive rise to any problems and may remain in the mixture. In thesubsequent sulfonation reaction, they are converted into theircorresponding alkyl sulfates.

The ratio of olefin to polygylcol ether in the mixture amountsadvantageously to from 9:1 to 1:4 parts by weight. These ratios can beexceeded in either direction, but in that case, the color of thereaction products increasingly deteriorates.

The sulfonation is conducted according to the known method. If gaseoussulfur trioxide is used as the sulfonating agent, it is used dilutedwith air or with an inert gas, the sulfur trioxide concentrationamounting to from 0.5 to 10 and preferably from 1 to 5 percent byvolume. Illustrative of the inert gases, which can be employed asdiluent, are, for example, nitrogen, carbon dioxide or sulfur dioxide.

Instead of the sulfur trioxide, as sulfonating agent, the equivalentamount of chlorosulfonic acid can also be advantageously used. Thehydrogen chloride that forms in the reaction should be removed, forexample, by passing a stream of air or inert gas through the reactionmixture, and continuing this operation for some time after thesulfonation has ended, or by alternatively operating under vacuum.

The sulfonation can be carried out discontinuously, or continuously,using a cocurrent or countercurrent fiow. It is recommended, however,that the reactants be intensively mixed during the sulfonation reaction.

The sulfonation reaction takes place at temperatures ranging from to 60C., and preferably at temperatures of from 10 to 40 C. As the reactionis an exothermic one, additional heat input is generally unnecessary. Inmost cases it is necessary to remove the excess reaction heat, and,accordingly, it is recommended that the optimum temperature bemaintained by appropriate cooling of the reaction vessel.

The reaction time depends to a great extent on the conditions selectedfor carrying out the reaction, such as the temperature, theconcentration of the sulfonating agent and the type of reactionapparatus used. Short re action times can be achieved particularly whenthe reaction mixture is intensively agitated by means of appropriatemechanical devices or is sprayed, or when reaction apparatus, which isused, are those operating on the thin layer or annular gap principle. Ifsmall quantities are used, the mixing action that is produced by theintroduction of the inert gas stream into the reaction mixture willsuffice under certain circumstances for achieving the desired degree ofsulfonation and nature of sulfonation product.

The sulfonation is continued until at least 1.0 and no more than 1.3mols, and preferably 1.05 to 1.2 mols of sulfur trioxide have beenabsorbed per mol of sulfonatable material. The olefins and thepolyglycol ethers which contain a free hydroxyl group in their moleculesare considered as the sulfonatable materials. With reference to thesedata, it is to be borne in mind that only the sulfur trioxide thatremains in the product enters into the computation of the molar ratio.

The sulfonation can also be carried out in two stages. In this case itis preferred to proceed in a first stage wherein the sulfonation iscarried out as described above, at a reaction temperature of 10 to 40 C.and with a sulfur trioxide concentration in the sulfonating gas of 1 to5% by volume. After the mixture to be sulfonated has absorbed 60 to ofthe total amount of sulfur trioxide to be used, it is advantageous thatin the second stage the temperature be reduced by about 5 to 10 C. andthe sulfur trioxide concentration in the gas reduced by at least 20%,Le, to a range of from 0.5 to 4% by volume. It may, furthermore, beadvantageous to increase the rate of feed of the sulfonation gas in thesecond stage, or reduce the time of action of the sulfonating agent.Finally, it is also possible to use gaseous sulfur trioxide in the firstsulfonating stage, as described above, and thereafter to usechlorosulfonic acid in the second stage. The amounts of sulfonatingagent to be used per mol of sulfouatable material likewise amount to 1.0to 1.3 mols, of which 0.5 to 1.0 and preferably 0.6 to 0.9 mol can besulfur trioxide and 0.2 to 0.6 and preferably 0.3 to 0.5 mol can bechlorosulfonic acid. During the addition of the chlorosulfonic acid, itis advantageous to pass a strong stream of air or inert gas through thereaction mixture, whereby there is removed a considerable part of thehydrogen chloride formed in the reaction. The introduction of air orinert gas into the reaction mixture should be continued for some timeafter all of the chlorosulfonic acid has been added. In this manner, itis possible to obtain a sulfonation product which is substantially freeof chlorine ions.

Often a sulfonation product having an even lighter color can be obtainedby this two-stage sulfonation. In most cases, however, such a procedureis unnecessary.

The sulfonation products as obtained according to the describedprocedures are then neutralized with alkalies, ammonia, organic ammoniumbases or alkaline earths and thereafter hydrolyzed by heating in anaqueous solution to temperatures of 80 to 200 C., using therefor thatamount of water whereby the crude sulfonation product is in the form ofa 7 to 75% solution. Hydrolysis at temperatures above C. is carried outin pressure vessels. In general, 60 to minutes are required forhydrolysis at temperatures of up to 100 C., and from 5 to 15 minutes areneeded for hydrolysis at 200 C. The quantity of the alkaline reactingsubstance used for the neutralization is calculated so that, afterneutralization of the sulfonic acid and any excess sulfonating agentthat might be present, enough still remains for the neutralization ofthe sulfonic acid that is formed in the hydrolysis. It is preferable towork with an excess that can amount to as much as 20% of thetheoretically necessary amount of alkali. Particularly suitableneutralization agents are the hydroxides, carbonates and bicarbonates ofsodium, potassium and ammonium, as well as organic bases, such as theprimary, secondary or tertiary amines or alkylolamines having 1 to 4 andpreferably two carbon atoms per alkyl or alkylol radical. If organicbases are used, these react with the sultones contained in the rawsulfonation product to form surface-active alkylsulfobetaines. It isalso possible however, first to neutralize the free sulfonic acids withan alkali metal or alkaline earth metal alkaline reacting agent and thento add one of the abovementioned organic bases in such quantity that inthe subsequent hydrolysis the sultones contained in the saponifiableportion are converted into alkylsulfobetaines.

If the hydrolysis of the raw sulfonation product is carried out attemperatures substantially higher than 100 C., a saponification of thepolyglycol ether sulfates occurs which increases with the temperatureand the heating time. However, since the unsulfated alkylpolyglycolethers that develop also possess valuable surface-active properties,particularly when the number of ethylene glycol groups in the moleculeis greater than 2, an additional possibility is thus provided forvarying the composition of the products of the process and adapting themto a particular application.

If for any particular purpose a still light colored sulfonation productis desired, a bleaching treatment can be carried out with theconventional oxygen-yielding bleaches. The sulfonation products obtainedby the process according to the invention contain few, if any, coloredby-products and are characterized by their excellent bleachability andlow consumption of bleaching agent. The hydrolysis and the bleaching canbe carried out simultaneously.

The light-colored mixtures manufactured according to the inventionconsist almost exclusively of surface-active materials. Depending on theprocedure that is followed, there are recovered mixtures of olefinsulfonates, or mixtures thereof with alkylsulfobetaines and alkylpolyglycol ether sulfates, or mixtures thereof with unsulfated alkylpolyglycol ethers or dialkyl polyglycol ethers and fatty alcoholsulfates if the polyglycol ethers used as the starting substancescontained free fatty alcohols. The unsulfonated olefin content of themixtures, however, amounts to less than 5%.

The products of the process have outstanding cleaning, wetting,emulsifying and dispersing properties and can be used in admixture withother wash-active substances and conventional synthetic agents andadditives in the formulation of detergents and washing compounds.Further, they can be used advantageously as additives in textileadjuvants. The properties of the products can be extensively adapted toa particular application. If the starting materials include polyglycolethers having a free hydroxyl group and the hydrolysis is carried out attemperatures of about 100 C., relatively high-sudsing prodnets areproduced which have a high cleaning power, such as is desired in finelaundry detergents, foaming cleaners and bathing and hair washingdetergents. The saponification of sulfated polyethylene glycol ethers orthe use of dialkylated polyethylene glycol ethers results, if there areat least 4 to 5 glycol ether groups in the molecule, in lowsudsingpreparations, suitable particularly for use as washing machinedetergents. If the end products contain mainly dialkylated or unsulfatedpolypropylene glycol ethers or unsulfated glycol ethers having 1 to 3ethylene glycol ether groups in their molecules, the products aresuitable primarily as emulsifiers.

The fact that the sulfonation of the mixtures of olefins and polyglycolethers even in the absence of inert solvents results in particularlylight-colored sulfonated products is surprising, since both the olefinsand the polyglycol ethers having a free hydroxyl group, if sulfonatedseparately with $0 under the same conditions, form relativelydark-colored sulfonation products which are technically usable onlyafter intensive bleaching has been carried out. As, furthermore,mixtures of alkyl polyglycol ethers and other sulfonatable materials,especially alkylbenzenes or fatty acid esters, under the same conditionsresult in the production of dark-colored sulfonation products having alow degree of sulfonation, it was not to be expected that the mixturesused according to the invention would behave in a fundamentallydifferent manner.

The following examples will further illustrate how the said inventionmay be carried out in practice, but the invention is not restricted tothese examples:

The olefins used in the following examples contained about 2% paraffinichydrocarbons. The color values as recited were determined in a 4" cellin the Lovibond Tintometer employing aqueous solutions which contained 5wt. percent of hydrolyzed and neutralized sulfonation product. Theunsulfonated olefins present in the end product were determined byextracting a sample of the hydrolyzed product three to four times usingthe same volume of benzine having a boiling point of to C. each time,removing the extractant by distillation, and determining the iodinenumber of the remaining oil. The amount of olefin thereby computed wasadded to the paraflins that were introduced with the starting material.The value thus obtained is set out hereinafter as the water-insolubleportion in percent by weight of waterfree end product. The mere weighingout of the benzine extract would produce false results since thepolygylcol ethers are partially soluble in the organic phase.

In Example 13, the use of a two-stage procedure is exemplified; in thefirst stage, the sulfonating was carried out with sulfur trioxide, andin the second stage chlorosulfonic acid was employed as sulfonatingagent.

EXAMPLE 1 In a flask with a 2-liter capacity, equipped with athermometer, a gas introduction tube extending down to the bottom of theflask, a gas exhaust tube and a high-speed agitator, a mixture of 112 g.(0.5 mol) of hexadecene-l (iodine No.=113) and 141 g. (0.5 mol) of aprimary alcohol having a chain length of C to C that had been reactedwith 2 mols of ethylene oxide were sulfonated, under intense agitation,by introducing into the olefin a gaseous mixture of S0 and aircontaining 3% of S0 by volume. 92 grams (1.15 moles) of S0 wereintroduced in the course of 45 minutes. The temperature of the reactionmixture was maintained at 20 to 35 C. by external cooling. After thesulfonation had been completed, the reaction product was poured withagitation into a solution of 52 g. (1.3 mols) of sodium hydroxide in 600ml. of water and refluxed for 3 hours. The water-insoluble content ofthe reaction product was determined and found to amount to 3.3%. A 5%neutral aqueous solution gave the following color values: yellow=16,red=3.1, blue=0.

The examples listed in Table I were performed in like manner. In thetable, the abbreviations EO and PO represent ethylene glycol ethergroups and propylene glycol ether groups, respectively.

TABLE I Insoluble Color Values Portions,

Example Olefin Polyglycol Ether sulfonating Agent percent Yellow RedBlue 2 112 g. (0.5 mol) ofn-hexadecene 141 g. (0.5 mol) prim. 012 014 89g. S03 (1.11 mols) 3. 5 16 2. 9 0

with the double bond ranalcohol 2 E0. domly distributed over the chain;I No.=111.

3 98 g. (0.5 mol) of n-tetradecene 141 g. (0.5 mol) same as 92 g. S0(1.15 mols) 3. 4 15 2. 5 0

with the double bond ran- Example 2. domly distributed over the chain; INo.=130.

4 116 g. (0.5 mol) of C15-Cm 141 g. (0.5 mol) same as 92 g. S0 (1.15mols) 3. 7 14 2. 1 0

alpha olefins, C No. 16.5, Example 2. I No.= 114.

5 156 g. (0.67 mol) same as 93 g. (0.33 mol) same as 92 g. S0 (1.15mols) 4.0 20 4.6 0

Example 4. Example 2.

6 174 g. (0.75 mol) same as 70.5 g. (0.25 mol) same as 92 g. S05 (1.15mols) 4. 4 25 6. 5 0

Example 4. Example 2.

200 g. (0.9 mol) same as 28 g. (0.1 mol) same as 92 g. 80 (1.15 mols) 4.8 27 13. 5 0

Example 4. Example 2.

8 174 g. (0.75 mol) same as 86 g. (0.25 mol) prim. Cir-C14 92 g. S0(1.15 mols) 3. 6 15 3. 4 0

Example 4. alcohol 3.1 E0.

9 116 g. (0.5 mol) same as 171 g. (0.5 mol) same as 92 g. S03 (1.15mols) 3. 4 15 5 0 Example 4. Example 8.

1O 116 g. (0.5 mol) same as 160 g. (0.5 mol) sec. Gig-C1 92 g. S03 (1.15mols) 5. 5 11 2. 8 0

Example 4. alcohol 3.1 E0.

11 186 g. (0.8 mol) same as 122 g. (0.2 mol) prim. C14 92 g. SO; (1.15mols) 4. 0 17 3.0 0

Example 4. alcohol 9 E0.

12 116 g. (0.5 mol) same as 141 g. (0.5 mol) same as g. (115.0 11 (1.2mols) 4. 8 18 3. 5 0

Example 4. Example 2.

TABLE IContinued Insoluble Color Values Portions,

Example Olefin Polyglycol Ether Sulionating Agent percent Yellow RedBlue 13.... 116 g. (0.5 mol) same as 141 g. (0.5mol) same as (a) 0.7 molof S03, (1)) 0.5 3.8 16 2 Example 4. Example 2. mol of CiSOaH.

14........; 93.5 g. (0.4 mol) C 0 alpha 138 g. (0.2 mol) see. On alcohol55 g. S03 (0.60 mol) 4. 2 7 1. 2 0

olefins C No. 16.5; I No.=111. 9 E0.

174 g. (0.75 mol) same as 173 g. (0.25 mol) same as 92 g. S0 (1.15 mols)4. 0 14 2. 4 0

Example 14. Example 14.

16 209 g. (0.9 mol) same as 69.5 g. (0.1 mol) same as 92 g. S0 (1.15mols) 3. 8 18 4. 7 0

Example 14. Example 14.

.. 174 g. (0.75 mol) same as 189 g. (0.2511101) prim. C1 92 g. S0 (1.15mols) 4. 6 0 1. 7 0

Example 14. alcohol 11 E0.

18 193 g. (0.83 mol) same as 128 g. (0.17 mol) same as 92 g. S0 (1.15mols) 4. 2 9 1. 9 0

Example 14. Example 17.

19 209 g. (0.9 mol) same as 75.5 g. (0.1 mol) same as 92 g. S03 (1.15mols) 4. 8 16 3. 8 0

Example 14. Example 17.

20.... 172 g. (0.8 mol) 2-hexyldecene-1 120 g. (0.2 mol) prim. C14 96 g.S03 (1.2 111015) 3. 3 8 1. 0 0

I No.=121. alcohol 9 E0.

21..... 172 g. (0.8 mol) T-methyl- 125 g. (0.2 mol) prim. Cr: 88 g. 50(1.1 m0is) 3.8 11 2. 1 0

penta-decene-6 I No.=120. alcohol 6 E0 3 PO.

To demonstrate the technical eifect, a series of comparative tests wascarried out under comparative conditions. The results of the tests aresummarized in Table II. In Experiments A and B, the olefins used inExamples 2 and 4 were sulfonated separately, and in Experiment C, thealkylpolyglycol ether used in Examples 1 to 4 was sulfonated separately.The products contain a higher percentage of unsulfonated,Water-insoluble components and are dark colored. Experiments D and Eshow that mixtures of polyglycol ethers and other sulfonatable startingmaterials are substantially less eiiective than the mixtures which areto be processed according to the invention.

TABLE II Insoluble Color Values Experi- Portions, ment Starting MaterialS0 Conditions 01 Reaction Percent Yellow Red Blue A 232 g. (1.0 mol)015-015 olefin, Average 92 g. (1.15 m01s).- Same as Example 1 6. 3 27 273. 3

No. 16.5; I No.:114. B 224 g. (1.0 mol) n-hexadecene with 92 g. (1.15mols) .d0 5.6 26 23 2.8

double bond randomly distributed over the chain; I No.:111. C 282 g. (1mol) prim. Clil-C alcohol 92 g. (1.15 mols) -d0 4.8 26 11.4 0

plus 2 E0; hydroxyl No.=199. D 121 g. (0.5 mol) dodecylbenzene plus 92g. (1.15 mo1s)...- hr. at (SO-65 C. 10 minutes post- 29.0 27 18 4 141 g.(0.5 mol) primary CITCH alcohol plus 2 E0.

E 118 g. (0.5 mol) hydrogenated palm kernel fatty acid methyl ester(GITCIB) plus 141 g. (0.5 mol) prim. (312-014 alcohol plus 2 E0.

reaction, 5 VOL-Percent mixture of S03 and air.

46. 0 Not measurable because too dark ture of S0 and air.

We claim:

1. A process for the preparation of surface-active sulfonates whichcomprises reacting an olefin having 8 to 22 carbon atoms in its moleculewith 1.0 to 1.3 mole per mol of said olefin gaseous sulfur trioxidediluted with an inert gas as sulfonating agent, in the presence of apolyglycol ether having the formula:

wherein R represents alkyl of 8 to 22 carbon atoms, R represents amember selected from the group of hydrogen and 'alkyl having I to 6carbon atoms, In is 2 or 3 and n is a whole number from 1 to 20 at atemperature of from O to 60 C., hydrolyzing the sulfonated olefinproduct thereby produced and thereafter neutralizing the resultingmixture with an alkaline neutralizing agent; the ratio of said olefin tosaid polyglycol ether is from 9:1 to 1:4 parts by weight.

2. A process according to claim 1 wherein said olefin is straightchained, has an internal or terminal double bond and contains from 12 to18 carbon atoms.

3. A process according to claim 1 wherein said olefin has the formulawherein R and R are each straight-chain alkyl having 1 to 18 carbonatoms and R is a member selected from the group consisting of hydrogenand straight-chain alkyl having 1 to 18 carbon atoms, with the provisothat at resultant mixture to a temperature of from 80 to 200 C.

7. A process according to claim 6 wherein sufiicient water is added tothe sulfonation reaction product to form a 7 to 75% solution.

8. A process according to claim 6 wherein said alkaline reacting agentis employed in an excess amounting to up to 20% of that theoreticallynecessary.

9. The surface-active olefin sulfonate characterized by light colorproduced by the process of claim 1.

10. The surface-active olefin sulfonate characterized by light colorproduced by the process of claim 6.

References Cited UNITED STATES PATENTS OTHER REFERENCES GilbertSulfonation and Related Reactions, pp. 43-46 and 367 (1965),Interscience Publishers, New York.

LEON D. ROSDOL, Primary Examiner P. E. WILLIS, Assistant Examiner U.S.Cl. X.R.

